Alex F.T.W. Rosenberg



Berkeley, Tuesday, 16 January 1979
(photo by George Bergman, with his permission)

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Alex F.T.W. Rosenberg, 80, died October 27, 2007, in Schwerte, Germany, after a long illness. He was born in Berlin, December 5, 1926. Alex's father, businessman Theodor, was long in denial about the Nazis, and didn't flee Germany, with his wife Rela and their two children, until August 1939. The family spent almost a year in Les-Plans-Sur-Bex, Switzerland, where Alex and his younger sister Edith attended school. After a brief stay in England, where thirteen year old Alex's command of English saw him involved in negotiations for the family's safe passage to Canada, the Rosenbergs resettled in Ontario.

Alex studied at the University of Toronto, where he distinguished himself (as part of the second place team) on the 8th William Lowell Putman Competition, held in March 1948. He earned a BA (Math/Physics, Div I) that year, and then an MA in 1949. David Dobbs, who was to do a PhD with him two decades later, recalls, "Alex was proud to the point of recalling the relevant page number of having been mentioned in a footnote in Coxeter's "The Real Projective Plane," as a promising undergraduate who had done something for one of Coxeter's geometry courses." (Cornell colleague David Henderson points out that Alex is credited in three footnotes in this landmark 1949 book, as well as being thanked in the preface "for helping with the proofs.")

Moving to Chicago for his doctoral work, Alex obtained his PhD from the University of Chicago in 1951, writing a thesis entitled "Subrings of Simple Rings with Minimal Ideals" written under the supervision of Irving Kaplansky (for more information of his mathematical genealogy, see http://www5.spelman.edu/~colm/alex.html.

After a one year postdoc at the University of Michigan, he began a decade long association with Northwestern University in 1952. That August, he married Beatrice F. Gershenson, of New York City. Their sons Theodore Joseph and David Michael were born in 1953 and 1956, respectively. Alex rose through the ranks to associate professor, and spent 1955-57 as a member of the Institute for Advanced Study in Princeton. He became a naturalized US citizen in 1959.

In 1961, he joined the faculty at Cornell University as professor of mathematics, and remained there for a quarter of a century. He was chairman of the department 1966-69, when it was at its largest, following which he spent a year as a visiting scholar at UCLA. He'd been at Queen Mary College, London, for the year 1963-64, and was attending the theatre when the news of Kennedy's assassination broke. During this year, he was also invited to lecture at the Hebrew University in Jerusalem.

He spent two semesters as visiting professor at Berkeley (spring 1961 and spring 1979). During his first sojourn there, he taught graduate algebra to a class which included a young Ron Graham, who remembers him as "a passionate teacher who loved his subject." He spent the fall of 1975 at Ludwig-Maximilians University in Munich, and the spring of 1976 at ETH Zurich, both as a von Humboldt Foundation Senior U.S. Scientist awardee. April & May 1980 saw him serve as Distinguished Lecturer in Mathematics at the University of Southern California, delivering a series of seven lectures. The year 1984-85 was spent at the University of Dortmund.

At Cornell, he was particularly active in library affairs, as the main department liaison with the outstanding mathematics library for two decades. In the 1970s, hard times led to the cancellation of several journals due to a shortage of funds, and Alex wrote a number of carefully targeted letters to former Cornell undergraduates who he thought might be in a position to help. In so doing, he started a process that persists to the present: his efforts (and generous personal donations) have been continued by his colleagues. Today these funds pay for a large portion of the library's monographs.

For many decades, he maintained a high profile in both the AMS and the MAA, serving as Editor of the Proceedings of the AMS (1960-65) and Editor of the American Mathematical Monthly (1974-76). He also did an under-recognized stint as editor of the Mathematical Problems section in the Monthly. In the early 1970s, he chaired the MAA's Committee on the Undergraduate Program in Mathematics.

University of Chicago, at the Herstein Conference, March 1987.

John Ewing, Executive Director of the AMS, notes: "Alex Rosenberg was a major force at the AMS for more than a quarter century, serving on editorial boards and governance bodies with incredible energy and devotion." He was on the AMS Board of Trustees in the period 1974-83, before that having being a member of the Executive Committee (1965-66) and Chair of the powerful Committee on Communication (1971-74).

Ken Ross, who served as Secretary of the MAA (1984-1989), recalls, "When I became an MAA officer, I heard statements about how our flagship journal, the Monthly, used to be a weak journal, but that three editors (roughly 1965-1976) were responsible for making it a good journal with high standards. These three were Ralph Boas, Harley Flanders, and Alex Rosenberg. A very believeable rumor."

His 50+ research articles included collaborations with Dan Zelinsky, Samuel Eilenberg, A. C. Zitronenbaum, Jerrold Kleinstein, Gerhard Hochschild, Steve Chase, Roger Ware, Manfred Knebusch, and Eberhard Becker.

Early in his career he worked on simple rings, homological properties of rings and modules, cohomology of associative and Lie algebras, Galois theory of rings, and Amitsur cohomology and the Brauer group of fields and commutative rings. Later he focused on quadratic forms and the Witt ring (and generalizations to higher level forms and signatures), and real algebraic geometry." One place where his name lives on is via the homological algebra Hochschild-Kostant-Rosenberg isomorphism. He also published and often presented on issues relating to undergraduate education and training programs for PhDs in mathematics.

Following a divorce in 1984, Alex remarried, in Germany, in 1985, and in 1986 he left Cornell to become department chair at UC Santa Barbara. His leadership role there was short-lived, and not without incident. In 1992 he co-organized, with Bill Jacob, an AMS Summer Research Institute on K-Theory and Algebraic Geometry with Applications to Quadratic Forms and Division Algebras at UCSB, also co-editing the published proceedings (AMS, 1995). A few years after his retirement in 1994, he moved back to Germany with his second wife, where he lived peacefully until his death.

Alex had 20 PhD students between 1957 and 1994. Of these, Vera Pless, Bodo Pareigis, Lindsay Childs, David Dobbs, Tom Craven and Vicki Powers went on to have PhD students of their own, bringing to 76 the total number of his mathematical descendents.

With Vicki Powers and Eberhard Becker, Germany, late 1980s

Many Cornell colleagues remember his professional dedication as well as his dark sense of humor and often colorful language. Says Peter Kahn, "He growled and grumbled and complained, but (in my hearing---at least most of the time) usually with a certain spark that let you know he was only partly serious. I think the most important thing I could say about Alex, beyond praising his mathematical talents and contributions, is that he cared deeply about the profession of mathematics in the broadest sense: from department administration, to teaching, to mentoring graduate students, to helping colleagues, etc. His level of caring was often intense and accounted for much of what might be called his acerbic quality."

Steve Chase, recalls, "My impression of Alex's attitude toward mathematical research is that it should be a collaborative effort. A great number of his papers were collaborations. One of my clearest memories of our collaboration of long ago is the fact that he was especially skilled at taking an afternoon of disorganized and occasionally incoherent discussion and blackboard work and transforming it all into intelligible and orderly exposition, often providing elegant elementary arguments in place of more advanced methods that we had originally used to obtain the results. He also wrote elegant manuscripts alone, eg., his 1961 Math. Zeitschrift paper on blocks in the theory of modular group representations. Alex was probably a genius at administration (as well as an especially committed and intense worker at it), and left his enduring mark on the several mathematical organizations that received the benefit of his efforts. Although he often complained about his administrative duties, it seemed to me that at bottom he enjoyed and sometimes reveled in them. His gift for creative verbal expression was complemented by several eye-catching posters that adorned the walls of his office."

Marshall Cohen observed, "Alex Rosenberg was a big-hearted man and champion of the underdog. I will always remember him fondly."

He is survived by his wife Brunhilde, of Schwerte, Germany, his adopted son Daniel, of Washington, DC, his former wife Beatrice, of Ithaca, NY, their son Ted of Rochester, NY, and his sister Edith, of Washington, DC. Sadly, he was predeceased by his son David, of New York City, in 2002.

Santa Barbara, circa 1998

Contributions to the Alex Rosenberg Book Fund may be sent to:

Alex Rosenberg Book Fund
c/o Steven W. Rockey
Mathematics Library
Malott Hall
Cornell University
Ithaca, NY 14853-4201

Checks should be made out to 'Cornell University' and clearly marked 'Alex Rosenberg Book Fund, Mathematics Library'. For more information, email Keith Dennis at dennis@rkd.math.cornell.edu.

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